diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirBodyResolveTransformer.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirBodyResolveTransformer.kt
index 9f29a8d8540..2989e69a63d 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirBodyResolveTransformer.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirBodyResolveTransformer.kt
@@ -561,7 +561,7 @@ open class FirBodyResolveTransformer(
 
     private fun FirWhenExpression.replaceReturnTypeIfNotExhaustive(): FirWhenExpression {
         if (!isExhaustive) {
-            resultType = resultType.resolvedTypeFromPrototype(session.builtinTypes.nullableAnyType.type)
+            resultType = resultType.resolvedTypeFromPrototype(session.builtinTypes.unitType.type)
         }
         return this
     }
diff --git a/compiler/fir/resolve/testData/resolve/exhaustiveness_boolean.txt b/compiler/fir/resolve/testData/resolve/exhaustiveness_boolean.txt
index cb3b2d9b52b..72efeabf878 100644
--- a/compiler/fir/resolve/testData/resolve/exhaustiveness_boolean.txt
+++ b/compiler/fir/resolve/testData/resolve/exhaustiveness_boolean.txt
@@ -1,6 +1,6 @@
 FILE: exhaustiveness_boolean.kt
     public final fun test_1(b: R|kotlin/Boolean|): R|kotlin/Unit| {
-        lval x: R|kotlin/Any?| = when (R|<local>/b|) {
+        lval x: R|kotlin/Unit| = when (R|<local>/b|) {
             ==($subj$, Boolean(true)) ->  {
                 Int(1)
             }
@@ -26,7 +26,7 @@ FILE: exhaustiveness_boolean.kt
 
     }
     public final fun test_2(b: R|kotlin/Boolean?|): R|kotlin/Unit| {
-        lval x: R|kotlin/Any?| = when (R|<local>/b|) {
+        lval x: R|kotlin/Unit| = when (R|<local>/b|) {
             ==($subj$, Boolean(true)) ->  {
                 Int(1)
             }
diff --git a/compiler/fir/resolve/testData/resolve/exhaustiveness_enum.txt b/compiler/fir/resolve/testData/resolve/exhaustiveness_enum.txt
index 2a1c00da6c1..86a64520bd7 100644
--- a/compiler/fir/resolve/testData/resolve/exhaustiveness_enum.txt
+++ b/compiler/fir/resolve/testData/resolve/exhaustiveness_enum.txt
@@ -27,7 +27,7 @@ FILE: exhaustiveness_enum.kt
 
     }
     public final fun test_1(e: R|Enum|): R|kotlin/Unit| {
-        lval a: R|kotlin/Any?| = when (R|<local>/e|) {
+        lval a: R|kotlin/Unit| = when (R|<local>/e|) {
             ==($subj$, Q|Enum.A|) ->  {
                 Int(1)
             }
@@ -36,7 +36,7 @@ FILE: exhaustiveness_enum.kt
             }
         }
 
-        lval b: R|kotlin/Any?| = when (R|<local>/e|) {
+        lval b: R|kotlin/Unit| = when (R|<local>/e|) {
             ==($subj$, Q|Enum.A|) ->  {
                 Int(1)
             }
@@ -71,7 +71,7 @@ FILE: exhaustiveness_enum.kt
 
     }
     public final fun test_2(e: R|Enum?|): R|kotlin/Unit| {
-        lval a: R|kotlin/Any?| = when (R|<local>/e|) {
+        lval a: R|kotlin/Unit| = when (R|<local>/e|) {
             ==($subj$, Q|Enum.A|) ->  {
                 Int(1)
             }
diff --git a/compiler/fir/resolve/testData/resolve/exhaustiveness_sealedClass.txt b/compiler/fir/resolve/testData/resolve/exhaustiveness_sealedClass.txt
index b075fd05446..dcc4a0f1f16 100644
--- a/compiler/fir/resolve/testData/resolve/exhaustiveness_sealedClass.txt
+++ b/compiler/fir/resolve/testData/resolve/exhaustiveness_sealedClass.txt
@@ -26,7 +26,7 @@ FILE: exhaustiveness_sealedClass.kt
 
     }
     public final fun test_1(e: R|Base|): R|kotlin/Unit| {
-        lval a: R|kotlin/Any?| = when (R|<local>/e|) {
+        lval a: R|kotlin/Unit| = when (R|<local>/e|) {
             ($subj$ is R|Base.A|) ->  {
                 Int(1)
             }
@@ -35,7 +35,7 @@ FILE: exhaustiveness_sealedClass.kt
             }
         }
 
-        lval b: R|kotlin/Any?| = when (R|<local>/e|) {
+        lval b: R|kotlin/Unit| = when (R|<local>/e|) {
             ($subj$ is R|Base.A|) ->  {
                 Int(1)
             }
@@ -70,7 +70,7 @@ FILE: exhaustiveness_sealedClass.kt
 
     }
     public final fun test_2(e: R|Base?|): R|kotlin/Unit| {
-        lval a: R|kotlin/Any?| = when (R|<local>/e|) {
+        lval a: R|kotlin/Unit| = when (R|<local>/e|) {
             ($subj$ is R|Base.A|) ->  {
                 Int(1)
             }
diff --git a/compiler/testData/ir/irText/expressions/bangbang.fir.txt b/compiler/testData/ir/irText/expressions/bangbang.fir.txt
index bc02e34c8cf..0ba9f82bc71 100644
--- a/compiler/testData/ir/irText/expressions/bangbang.fir.txt
+++ b/compiler/testData/ir/irText/expressions/bangbang.fir.txt
@@ -59,7 +59,7 @@ FILE fqName:<root> fileName:/bangbang.kt
     TYPE_PARAMETER name:X index:0 variance: superTypes:[]
     VALUE_PARAMETER name:a index:0 type:X of <root>.test4
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=kotlin.String?
             GET_VAR 'a: X of <root>.test4 declared in <root>.test4' type=X of <root>.test4 origin=null
@@ -76,7 +76,7 @@ FILE fqName:<root> fileName:/bangbang.kt
               BRANCH
                 if: CONST Boolean type=kotlin.Boolean value=true
                 then: GET_VAR 'val <bangbang>: kotlin.String? [val] declared in <root>.test4' type=kotlin.String origin=null
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=kotlin.String?
             GET_VAR 'a: X of <root>.test4 declared in <root>.test4' type=X of <root>.test4 origin=null
diff --git a/compiler/testData/ir/irText/expressions/breakContinueInLoopHeader.fir.txt b/compiler/testData/ir/irText/expressions/breakContinueInLoopHeader.fir.txt
index ed4f0c4c0f1..8f60da1416a 100644
--- a/compiler/testData/ir/irText/expressions/breakContinueInLoopHeader.fir.txt
+++ b/compiler/testData/ir/irText/expressions/breakContinueInLoopHeader.fir.txt
@@ -103,7 +103,7 @@ FILE fqName:<root> fileName:/breakContinueInLoopHeader.kt
         CONST Int type=kotlin.Int value=0
       WHILE label=Outer origin=WHILE_LOOP
         condition: CONST Boolean type=kotlin.Boolean value=true
-        body: BLOCK type=kotlin.Any? origin=null
+        body: BLOCK type=kotlin.Unit origin=null
           VAR name:<unary> type:kotlin.Int [val]
             GET_VAR 'var i: kotlin.Int [var] declared in <root>.test5' type=kotlin.Int origin=null
           SET_VAR 'var i: kotlin.Int [var] declared in <root>.test5' type=kotlin.Int origin=null
@@ -129,7 +129,7 @@ FILE fqName:<root> fileName:/breakContinueInLoopHeader.kt
               BRANCH
                 if: CONST Boolean type=kotlin.Boolean value=true
                 then: BREAK label=null loop.label=Outer
-          WHEN type=kotlin.Any? origin=IF
+          WHEN type=kotlin.Unit origin=IF
             BRANCH
               if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
                 arg0: GET_VAR 'var i: kotlin.Int [var] declared in <root>.test5' type=kotlin.Int origin=null
diff --git a/compiler/testData/ir/irText/expressions/breakContinueInWhen.fir.txt b/compiler/testData/ir/irText/expressions/breakContinueInWhen.fir.txt
index 28ce84726e7..6f9d9a0c93f 100644
--- a/compiler/testData/ir/irText/expressions/breakContinueInWhen.fir.txt
+++ b/compiler/testData/ir/irText/expressions/breakContinueInWhen.fir.txt
@@ -19,11 +19,11 @@ FILE fqName:<root> fileName:/breakContinueInWhen.kt
       WHILE label=null origin=FOR_LOOP_INNER_WHILE
         condition: CALL 'public abstract fun hasNext (): kotlin.Boolean declared in kotlin.collections.Iterator' type=kotlin.Boolean origin=null
           $this: GET_VAR 'val <iterator>: kotlin.collections.IntIterator [val] declared in <root>.testBreakFor' type=kotlin.collections.IntIterator origin=null
-        body: BLOCK type=kotlin.Any? origin=null
+        body: BLOCK type=kotlin.Unit origin=null
           VAR name:x type:kotlin.Int [val]
             CALL 'public final fun next (): kotlin.Int declared in kotlin.collections.IntIterator' type=kotlin.Int origin=null
               $this: GET_VAR 'val <iterator>: kotlin.collections.IntIterator [val] declared in <root>.testBreakFor' type=kotlin.collections.IntIterator origin=null
-          WHEN type=kotlin.Any? origin=WHEN
+          WHEN type=kotlin.Unit origin=WHEN
             BRANCH
               if: CALL 'public final fun greater (arg0: kotlin.Int, arg1: kotlin.Int): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=GT
                 arg0: GET_VAR 'var k: kotlin.Int [var] declared in <root>.testBreakFor' type=kotlin.Int origin=null
@@ -37,7 +37,7 @@ FILE fqName:<root> fileName:/breakContinueInWhen.kt
         condition: CALL 'public final fun less (arg0: kotlin.Int, arg1: kotlin.Int): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=LT
           arg0: GET_VAR 'var k: kotlin.Int [var] declared in <root>.testBreakWhile' type=kotlin.Int origin=null
           arg1: CONST Int type=kotlin.Int value=10
-        body: WHEN type=kotlin.Any? origin=WHEN
+        body: WHEN type=kotlin.Unit origin=WHEN
           BRANCH
             if: CALL 'public final fun greater (arg0: kotlin.Int, arg1: kotlin.Int): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=GT
               arg0: GET_VAR 'var k: kotlin.Int [var] declared in <root>.testBreakWhile' type=kotlin.Int origin=null
@@ -48,7 +48,7 @@ FILE fqName:<root> fileName:/breakContinueInWhen.kt
       VAR name:k type:kotlin.Int [var]
         CONST Int type=kotlin.Int value=0
       DO_WHILE label=null origin=DO_WHILE_LOOP
-        body: WHEN type=kotlin.Any? origin=WHEN
+        body: WHEN type=kotlin.Unit origin=WHEN
           BRANCH
             if: CALL 'public final fun greater (arg0: kotlin.Int, arg1: kotlin.Int): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=GT
               arg0: GET_VAR 'var k: kotlin.Int [var] declared in <root>.testBreakDoWhile' type=kotlin.Int origin=null
@@ -77,11 +77,11 @@ FILE fqName:<root> fileName:/breakContinueInWhen.kt
       WHILE label=null origin=FOR_LOOP_INNER_WHILE
         condition: CALL 'public abstract fun hasNext (): kotlin.Boolean declared in kotlin.collections.Iterator' type=kotlin.Boolean origin=null
           $this: GET_VAR 'val <iterator>: kotlin.collections.IntIterator [val] declared in <root>.testContinueFor' type=kotlin.collections.IntIterator origin=null
-        body: BLOCK type=kotlin.Any? origin=null
+        body: BLOCK type=kotlin.Unit origin=null
           VAR name:x type:kotlin.Int [val]
             CALL 'public final fun next (): kotlin.Int declared in kotlin.collections.IntIterator' type=kotlin.Int origin=null
               $this: GET_VAR 'val <iterator>: kotlin.collections.IntIterator [val] declared in <root>.testContinueFor' type=kotlin.collections.IntIterator origin=null
-          WHEN type=kotlin.Any? origin=WHEN
+          WHEN type=kotlin.Unit origin=WHEN
             BRANCH
               if: CALL 'public final fun greater (arg0: kotlin.Int, arg1: kotlin.Int): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=GT
                 arg0: GET_VAR 'var k: kotlin.Int [var] declared in <root>.testContinueFor' type=kotlin.Int origin=null
@@ -95,7 +95,7 @@ FILE fqName:<root> fileName:/breakContinueInWhen.kt
         condition: CALL 'public final fun less (arg0: kotlin.Int, arg1: kotlin.Int): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=LT
           arg0: GET_VAR 'var k: kotlin.Int [var] declared in <root>.testContinueWhile' type=kotlin.Int origin=null
           arg1: CONST Int type=kotlin.Int value=10
-        body: WHEN type=kotlin.Any? origin=WHEN
+        body: WHEN type=kotlin.Unit origin=WHEN
           BRANCH
             if: CALL 'public final fun greater (arg0: kotlin.Int, arg1: kotlin.Int): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=GT
               arg0: GET_VAR 'var k: kotlin.Int [var] declared in <root>.testContinueWhile' type=kotlin.Int origin=null
@@ -115,7 +115,7 @@ FILE fqName:<root> fileName:/breakContinueInWhen.kt
             CALL 'public final fun inc (): kotlin.Int declared in kotlin.Int' type=kotlin.Int origin=null
               $this: GET_VAR 'val <unary>: kotlin.Int [val] declared in <root>.testContinueDoWhile' type=kotlin.Int origin=null
           GET_VAR 'var k: kotlin.Int [var] declared in <root>.testContinueDoWhile' type=kotlin.Int origin=null
-          WHEN type=kotlin.Any? origin=WHEN
+          WHEN type=kotlin.Unit origin=WHEN
             BRANCH
               if: CALL 'public final fun greater (arg0: kotlin.Int, arg1: kotlin.Int): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=GT
                 arg0: GET_VAR 'var k: kotlin.Int [var] declared in <root>.testContinueDoWhile' type=kotlin.Int origin=null
@@ -128,7 +128,7 @@ FILE fqName:<root> fileName:/breakContinueInWhen.kt
         condition: CALL 'public final fun less (arg0: kotlin.Int, arg1: kotlin.Int): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=LT
           arg0: GET_VAR 'var k: kotlin.Int [var] declared in <root>.testContinueDoWhile' type=kotlin.Int origin=null
           arg1: CONST Int type=kotlin.Int value=10
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
diff --git a/compiler/testData/ir/irText/expressions/elvis.fir.txt b/compiler/testData/ir/irText/expressions/elvis.fir.txt
index 9bea8c04a2c..e916d3367da 100644
--- a/compiler/testData/ir/irText/expressions/elvis.fir.txt
+++ b/compiler/testData/ir/irText/expressions/elvis.fir.txt
@@ -50,13 +50,13 @@ FILE fqName:<root> fileName:/elvis.kt
     VALUE_PARAMETER name:a index:0 type:kotlin.Any?
     VALUE_PARAMETER name:b index:1 type:kotlin.Any?
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=kotlin.String
             GET_VAR 'b: kotlin.Any? declared in <root>.test3' type=kotlin.Any? origin=null
           then: RETURN type=kotlin.Nothing from='public final fun test3 (a: kotlin.Any?, b: kotlin.Any?): kotlin.String declared in <root>'
             CONST String type=kotlin.String value=""
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=kotlin.String?
             GET_VAR 'a: kotlin.Any? declared in <root>.test3' type=kotlin.Any? origin=null
diff --git a/compiler/testData/ir/irText/expressions/floatingPointComparisons/whenByFloatingPoint.fir.txt b/compiler/testData/ir/irText/expressions/floatingPointComparisons/whenByFloatingPoint.fir.txt
index 4d2f06c4834..1b8f933ec20 100644
--- a/compiler/testData/ir/irText/expressions/floatingPointComparisons/whenByFloatingPoint.fir.txt
+++ b/compiler/testData/ir/irText/expressions/floatingPointComparisons/whenByFloatingPoint.fir.txt
@@ -17,7 +17,7 @@ FILE fqName:<root> fileName:/whenByFloatingPoint.kt
   FUN name:testSmartCastInWhenSubject visibility:public modality:FINAL <> (x:kotlin.Any) returnType:kotlin.Int
     VALUE_PARAMETER name:x index:0 type:kotlin.Any
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=kotlin.Double
             GET_VAR 'x: kotlin.Any declared in <root>.testSmartCastInWhenSubject' type=kotlin.Any origin=null
@@ -40,7 +40,7 @@ FILE fqName:<root> fileName:/whenByFloatingPoint.kt
     VALUE_PARAMETER name:x index:0 type:kotlin.Double
     VALUE_PARAMETER name:y index:1 type:kotlin.Any
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=kotlin.Double
             GET_VAR 'y: kotlin.Any declared in <root>.testSmartCastInWhenCondition' type=kotlin.Any origin=null
@@ -83,14 +83,14 @@ FILE fqName:<root> fileName:/whenByFloatingPoint.kt
     VALUE_PARAMETER name:x index:0 type:kotlin.Any
     VALUE_PARAMETER name:y index:1 type:kotlin.Any
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=kotlin.Double
             GET_VAR 'x: kotlin.Any declared in <root>.testSmartCastToDifferentTypes' type=kotlin.Any origin=null
           then: RETURN type=kotlin.Nothing from='public final fun testSmartCastToDifferentTypes (x: kotlin.Any, y: kotlin.Any): kotlin.Int declared in <root>'
             CALL 'public final fun unaryMinus (): kotlin.Int declared in kotlin.Int' type=kotlin.Int origin=null
               $this: CONST Int type=kotlin.Int value=1
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=kotlin.Float
             GET_VAR 'y: kotlin.Any declared in <root>.testSmartCastToDifferentTypes' type=kotlin.Any origin=null
diff --git a/compiler/testData/ir/irText/expressions/ifElseIf.fir.txt b/compiler/testData/ir/irText/expressions/ifElseIf.fir.txt
index 4828831aa20..6556643aa7d 100644
--- a/compiler/testData/ir/irText/expressions/ifElseIf.fir.txt
+++ b/compiler/testData/ir/irText/expressions/ifElseIf.fir.txt
@@ -31,7 +31,7 @@ FILE fqName:<root> fileName:/ifElseIf.kt
         BRANCH
           if: CONST Boolean type=kotlin.Boolean value=true
           then: CONST Boolean type=kotlin.Boolean value=true
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: GET_VAR 'flag: kotlin.Boolean declared in <root>.testEmptyBranches1' type=kotlin.Boolean origin=null
           then: CONST Boolean type=kotlin.Boolean value=true
diff --git a/compiler/testData/ir/irText/expressions/implicitCastInReturnFromConstructor.fir.txt b/compiler/testData/ir/irText/expressions/implicitCastInReturnFromConstructor.fir.txt
index 9b84cd16efc..e69cf46dc11 100644
--- a/compiler/testData/ir/irText/expressions/implicitCastInReturnFromConstructor.fir.txt
+++ b/compiler/testData/ir/irText/expressions/implicitCastInReturnFromConstructor.fir.txt
@@ -8,7 +8,7 @@ FILE fqName:<root> fileName:/implicitCastInReturnFromConstructor.kt
     CONSTRUCTOR visibility:public <> (x:kotlin.Any?) returnType:<root>.C
       VALUE_PARAMETER name:x index:0 type:kotlin.Any?
       BLOCK_BODY
-        WHEN type=kotlin.Any? origin=IF
+        WHEN type=kotlin.Unit origin=IF
           BRANCH
             if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=kotlin.Unit
               GET_VAR 'x: kotlin.Any? declared in <root>.C.<init>' type=kotlin.Any? origin=null
diff --git a/compiler/testData/ir/irText/expressions/implicitCastToNonNull.fir.txt b/compiler/testData/ir/irText/expressions/implicitCastToNonNull.fir.txt
index 32025ebd925..787f5f5fa4e 100644
--- a/compiler/testData/ir/irText/expressions/implicitCastToNonNull.fir.txt
+++ b/compiler/testData/ir/irText/expressions/implicitCastToNonNull.fir.txt
@@ -62,7 +62,7 @@ FILE fqName:<root> fileName:/implicitCastToNonNull.kt
     VALUE_PARAMETER name:x index:0 type:T of <root>.test5
     VALUE_PARAMETER name:fn index:1 type:kotlin.Function1<S of <root>.test5, kotlin.Unit>
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
diff --git a/compiler/testData/ir/irText/expressions/kt24804.fir.txt b/compiler/testData/ir/irText/expressions/kt24804.fir.txt
index 601222c1741..27b548313f4 100644
--- a/compiler/testData/ir/irText/expressions/kt24804.fir.txt
+++ b/compiler/testData/ir/irText/expressions/kt24804.fir.txt
@@ -10,21 +10,21 @@ FILE fqName:<root> fileName:/kt24804.kt
       VAR name:z type:kotlin.Int [var]
         CONST Int type=kotlin.Int value=10
       DO_WHILE label=l2 origin=DO_WHILE_LOOP
-        body: BLOCK type=kotlin.Any? origin=null
+        body: BLOCK type=kotlin.Unit origin=null
           SET_VAR 'var z: kotlin.Int [var] declared in <root>.run' type=kotlin.Int origin=null
             CONST Int type=kotlin.Int value=1
-          WHEN type=kotlin.Any? origin=IF
+          WHEN type=kotlin.Unit origin=IF
             BRANCH
               if: CALL 'public final fun greater (arg0: kotlin.Int, arg1: kotlin.Int): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=GT
                 arg0: GET_VAR 'var z: kotlin.Int [var] declared in <root>.run' type=kotlin.Int origin=null
                 arg1: CONST Int type=kotlin.Int value=100
               then: RETURN type=kotlin.Nothing from='public final fun run (x: kotlin.Boolean, y: kotlin.Boolean): kotlin.String declared in <root>'
                 CONST String type=kotlin.String value="NOT_OK"
-          WHEN type=kotlin.Any? origin=IF
+          WHEN type=kotlin.Unit origin=IF
             BRANCH
               if: GET_VAR 'x: kotlin.Boolean declared in <root>.run' type=kotlin.Boolean origin=null
               then: ERROR_EXPR 'Unbound loop: continue@@@[ERROR_EXPR(Cannot bind label l1 to a loop)] ' type=kotlin.Nothing
-          WHEN type=kotlin.Any? origin=IF
+          WHEN type=kotlin.Unit origin=IF
             BRANCH
               if: GET_VAR 'y: kotlin.Boolean declared in <root>.run' type=kotlin.Boolean origin=null
               then: CONTINUE label=l2 loop.label=l2
diff --git a/compiler/testData/ir/irText/expressions/kt27933.fir.txt b/compiler/testData/ir/irText/expressions/kt27933.fir.txt
index b241bb649a1..8103ccaf2aa 100644
--- a/compiler/testData/ir/irText/expressions/kt27933.fir.txt
+++ b/compiler/testData/ir/irText/expressions/kt27933.fir.txt
@@ -15,7 +15,7 @@ FILE fqName:<root> fileName:/kt27933.kt
           then: BLOCK type=kotlin.Unit origin=null
             SET_VAR 'var r: kotlin.String [var] declared in <root>.box' type=kotlin.String origin=null
               CONST String type=kotlin.String value="O"
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
             arg0: GET_VAR 'var r: kotlin.String [var] declared in <root>.box' type=kotlin.String origin=null
diff --git a/compiler/testData/ir/irText/expressions/sam/samConversionsWithSmartCasts.fir.txt b/compiler/testData/ir/irText/expressions/sam/samConversionsWithSmartCasts.fir.txt
index aa3bddd7dfa..be9cc6cb1ec 100644
--- a/compiler/testData/ir/irText/expressions/sam/samConversionsWithSmartCasts.fir.txt
+++ b/compiler/testData/ir/irText/expressions/sam/samConversionsWithSmartCasts.fir.txt
@@ -2,7 +2,7 @@ FILE fqName:<root> fileName:/samConversionsWithSmartCasts.kt
   FUN name:test1 visibility:public modality:FINAL <> (a:kotlin.Function0<kotlin.Unit>) returnType:kotlin.Unit
     VALUE_PARAMETER name:a index:0 type:kotlin.Function0<kotlin.Unit>
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=java.lang.Runnable
             GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test1' type=kotlin.Function0<kotlin.Unit> origin=null
@@ -11,7 +11,7 @@ FILE fqName:<root> fileName:/samConversionsWithSmartCasts.kt
   FUN name:test2 visibility:public modality:FINAL <> (a:kotlin.Function0<kotlin.Unit>) returnType:kotlin.Unit
     VALUE_PARAMETER name:a index:0 type:kotlin.Function0<kotlin.Unit>
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=java.lang.Runnable
             GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test2' type=kotlin.Function0<kotlin.Unit> origin=null
@@ -21,7 +21,7 @@ FILE fqName:<root> fileName:/samConversionsWithSmartCasts.kt
   FUN name:test3 visibility:public modality:FINAL <> (a:kotlin.Function0<kotlin.Unit>) returnType:kotlin.Unit
     VALUE_PARAMETER name:a index:0 type:kotlin.Function0<kotlin.Unit>
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=java.lang.Runnable
             GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test3' type=kotlin.Function0<kotlin.Unit> origin=null
@@ -33,7 +33,7 @@ FILE fqName:<root> fileName:/samConversionsWithSmartCasts.kt
     VALUE_PARAMETER name:a index:0 type:kotlin.Function0<kotlin.Unit>
     VALUE_PARAMETER name:b index:1 type:kotlin.Function0<kotlin.Unit>
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=java.lang.Runnable
             GET_VAR 'a: kotlin.Function0<kotlin.Unit> declared in <root>.test4' type=kotlin.Function0<kotlin.Unit> origin=null
@@ -44,7 +44,7 @@ FILE fqName:<root> fileName:/samConversionsWithSmartCasts.kt
   FUN name:test5 visibility:public modality:FINAL <> (a:kotlin.Any) returnType:kotlin.Unit
     VALUE_PARAMETER name:a index:0 type:kotlin.Any
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=java.lang.Runnable
             GET_VAR 'a: kotlin.Any declared in <root>.test5' type=kotlin.Any origin=null
@@ -54,7 +54,7 @@ FILE fqName:<root> fileName:/samConversionsWithSmartCasts.kt
   FUN name:test5x visibility:public modality:FINAL <> (a:kotlin.Any) returnType:kotlin.Unit
     VALUE_PARAMETER name:a index:0 type:kotlin.Any
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=java.lang.Runnable
             GET_VAR 'a: kotlin.Any declared in <root>.test5x' type=kotlin.Any origin=null
diff --git a/compiler/testData/ir/irText/expressions/setFieldWithImplicitCast.fir.txt b/compiler/testData/ir/irText/expressions/setFieldWithImplicitCast.fir.txt
index a6a2d94310a..6f3b1cc2016 100644
--- a/compiler/testData/ir/irText/expressions/setFieldWithImplicitCast.fir.txt
+++ b/compiler/testData/ir/irText/expressions/setFieldWithImplicitCast.fir.txt
@@ -9,7 +9,7 @@ FILE fqName:<root> fileName:/Derived.kt
       $this: VALUE_PARAMETER name:<this> type:<root>.Derived
       VALUE_PARAMETER name:v index:0 type:kotlin.Any
       BLOCK_BODY
-        WHEN type=kotlin.Any? origin=IF
+        WHEN type=kotlin.Unit origin=IF
           BRANCH
             if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=kotlin.String
               GET_VAR 'v: kotlin.Any declared in <root>.Derived.setValue' type=kotlin.Any origin=null
diff --git a/compiler/testData/ir/irText/expressions/smartCasts.fir.txt b/compiler/testData/ir/irText/expressions/smartCasts.fir.txt
index 7b974f10638..d6166c8c12a 100644
--- a/compiler/testData/ir/irText/expressions/smartCasts.fir.txt
+++ b/compiler/testData/ir/irText/expressions/smartCasts.fir.txt
@@ -18,7 +18,7 @@ FILE fqName:<root> fileName:/smartCasts.kt
   FUN name:test1 visibility:public modality:FINAL <> (x:kotlin.Any) returnType:kotlin.Unit
     VALUE_PARAMETER name:x index:0 type:kotlin.Any
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=kotlin.String
             GET_VAR 'x: kotlin.Any declared in <root>.test1' type=kotlin.Any origin=null
@@ -38,7 +38,7 @@ FILE fqName:<root> fileName:/smartCasts.kt
   FUN name:test2 visibility:public modality:FINAL <> (x:kotlin.Any) returnType:kotlin.String
     VALUE_PARAMETER name:x index:0 type:kotlin.Any
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=kotlin.String
             GET_VAR 'x: kotlin.Any declared in <root>.test2' type=kotlin.Any origin=null
@@ -50,7 +50,7 @@ FILE fqName:<root> fileName:/smartCasts.kt
   FUN name:test3 visibility:public modality:FINAL <> (x:kotlin.Any) returnType:kotlin.String
     VALUE_PARAMETER name:x index:0 type:kotlin.Any
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=kotlin.String
             GET_VAR 'x: kotlin.Any declared in <root>.test3' type=kotlin.Any origin=null
diff --git a/compiler/testData/ir/irText/expressions/smartCastsWithDestructuring.fir.txt b/compiler/testData/ir/irText/expressions/smartCastsWithDestructuring.fir.txt
index 5d292cd8a56..8d074ef72f8 100644
--- a/compiler/testData/ir/irText/expressions/smartCastsWithDestructuring.fir.txt
+++ b/compiler/testData/ir/irText/expressions/smartCastsWithDestructuring.fir.txt
@@ -42,7 +42,7 @@ FILE fqName:<root> fileName:/smartCastsWithDestructuring.kt
   FUN name:test visibility:public modality:FINAL <> (x:<root>.I1) returnType:kotlin.Unit
     VALUE_PARAMETER name:x index:0 type:<root>.I1
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=<root>.I2
             GET_VAR 'x: <root>.I1 declared in <root>.test' type=<root>.I1 origin=null
diff --git a/compiler/testData/ir/irText/expressions/throw.fir.txt b/compiler/testData/ir/irText/expressions/throw.fir.txt
index 02ae7954324..ff79ded8a7a 100644
--- a/compiler/testData/ir/irText/expressions/throw.fir.txt
+++ b/compiler/testData/ir/irText/expressions/throw.fir.txt
@@ -6,7 +6,7 @@ FILE fqName:<root> fileName:/throw.kt
   FUN name:testImplicitCast visibility:public modality:FINAL <> (a:kotlin.Any) returnType:kotlin.Unit
     VALUE_PARAMETER name:a index:0 type:kotlin.Any
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=kotlin.Throwable
             GET_VAR 'a: kotlin.Any declared in <root>.testImplicitCast' type=kotlin.Any origin=null
diff --git a/compiler/testData/ir/irText/expressions/tryCatchWithImplicitCast.fir.txt b/compiler/testData/ir/irText/expressions/tryCatchWithImplicitCast.fir.txt
index 2524d311956..9c2c32bbaed 100644
--- a/compiler/testData/ir/irText/expressions/tryCatchWithImplicitCast.fir.txt
+++ b/compiler/testData/ir/irText/expressions/tryCatchWithImplicitCast.fir.txt
@@ -2,7 +2,7 @@ FILE fqName:<root> fileName:/tryCatchWithImplicitCast.kt
   FUN name:testImplicitCast visibility:public modality:FINAL <> (a:kotlin.Any) returnType:kotlin.Unit
     VALUE_PARAMETER name:a index:0 type:kotlin.Any
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=kotlin.String
             GET_VAR 'a: kotlin.Any declared in <root>.testImplicitCast' type=kotlin.Any origin=null
diff --git a/compiler/testData/ir/irText/expressions/useImportedMember.fir.txt b/compiler/testData/ir/irText/expressions/useImportedMember.fir.txt
index c3de50d3c44..a8b21c00efb 100644
--- a/compiler/testData/ir/irText/expressions/useImportedMember.fir.txt
+++ b/compiler/testData/ir/irText/expressions/useImportedMember.fir.txt
@@ -149,7 +149,7 @@ FILE fqName:<root> fileName:/useImportedMember.kt
       VALUE_PARAMETER name:g index:0 type:kotlin.String
   FUN name:box visibility:public modality:FINAL <> () returnType:kotlin.String
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
@@ -159,7 +159,7 @@ FILE fqName:<root> fileName:/useImportedMember.kt
               arg1: CONST Int type=kotlin.Int value=1
           then: RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
             CONST String type=kotlin.String value="1"
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
@@ -169,7 +169,7 @@ FILE fqName:<root> fileName:/useImportedMember.kt
               arg1: CONST Int type=kotlin.Int value=2
           then: RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
             CONST String type=kotlin.String value="2"
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
@@ -178,7 +178,7 @@ FILE fqName:<root> fileName:/useImportedMember.kt
               arg1: CONST Int type=kotlin.Int value=3
           then: RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
             CONST String type=kotlin.String value="3"
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
@@ -190,7 +190,7 @@ FILE fqName:<root> fileName:/useImportedMember.kt
       SET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:p type:kotlin.Int visibility:private' type=kotlin.Unit origin=null
         receiver: GET_VAR '<this>: <root>.C declared in <root>.C' type=<root>.C origin=null
         value: CONST Int type=kotlin.Int value=5
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
@@ -199,7 +199,7 @@ FILE fqName:<root> fileName:/useImportedMember.kt
               arg1: CONST Int type=kotlin.Int value=5
           then: RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
             CONST String type=kotlin.String value="5"
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
@@ -208,7 +208,7 @@ FILE fqName:<root> fileName:/useImportedMember.kt
               arg1: CONST Int type=kotlin.Int value=6
           then: RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
             CONST String type=kotlin.String value="6"
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
@@ -219,7 +219,7 @@ FILE fqName:<root> fileName:/useImportedMember.kt
               arg1: CONST String type=kotlin.String value="7"
           then: RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
             CONST String type=kotlin.String value="7"
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
@@ -228,7 +228,7 @@ FILE fqName:<root> fileName:/useImportedMember.kt
               arg1: CONST String type=kotlin.String value="8"
           then: RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
             CONST String type=kotlin.String value="8"
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
@@ -238,7 +238,7 @@ FILE fqName:<root> fileName:/useImportedMember.kt
               arg1: CONST Int type=kotlin.Int value=9
           then: RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
             CONST String type=kotlin.String value="9"
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
@@ -247,7 +247,7 @@ FILE fqName:<root> fileName:/useImportedMember.kt
               arg1: CONST String type=kotlin.String value="10"
           then: RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
             CONST String type=kotlin.String value="10"
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
diff --git a/compiler/testData/ir/irText/expressions/varargWithImplicitCast.fir.txt b/compiler/testData/ir/irText/expressions/varargWithImplicitCast.fir.txt
index cc4a0a0de43..3b93d65dfcb 100644
--- a/compiler/testData/ir/irText/expressions/varargWithImplicitCast.fir.txt
+++ b/compiler/testData/ir/irText/expressions/varargWithImplicitCast.fir.txt
@@ -2,7 +2,7 @@ FILE fqName:<root> fileName:/varargWithImplicitCast.kt
   FUN name:testScalar visibility:public modality:FINAL <> (a:kotlin.Any) returnType:kotlin.IntArray
     VALUE_PARAMETER name:a index:0 type:kotlin.Any
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=kotlin.Int
             GET_VAR 'a: kotlin.Any declared in <root>.testScalar' type=kotlin.Any origin=null
@@ -14,7 +14,7 @@ FILE fqName:<root> fileName:/varargWithImplicitCast.kt
   FUN name:testSpread visibility:public modality:FINAL <> (a:kotlin.Any) returnType:kotlin.IntArray
     VALUE_PARAMETER name:a index:0 type:kotlin.Any
     BLOCK_BODY
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=kotlin.IntArray
             GET_VAR 'a: kotlin.Any declared in <root>.testSpread' type=kotlin.Any origin=null
diff --git a/compiler/testData/ir/irText/expressions/whenCoercedToUnit.fir.txt b/compiler/testData/ir/irText/expressions/whenCoercedToUnit.fir.txt
index 18842a2d93a..da87de4dc9e 100644
--- a/compiler/testData/ir/irText/expressions/whenCoercedToUnit.fir.txt
+++ b/compiler/testData/ir/irText/expressions/whenCoercedToUnit.fir.txt
@@ -2,9 +2,9 @@ FILE fqName:<root> fileName:/whenCoercedToUnit.kt
   FUN name:foo visibility:public modality:FINAL <> (x:kotlin.Int) returnType:kotlin.Unit
     VALUE_PARAMETER name:x index:0 type:kotlin.Int
     BLOCK_BODY
-      BLOCK type=kotlin.Any? origin=WHEN
+      BLOCK type=kotlin.Unit origin=WHEN
         VAR IR_TEMPORARY_VARIABLE name:tmp0_subject type:kotlin.Int [val]
-        WHEN type=kotlin.Any? origin=WHEN
+        WHEN type=kotlin.Unit origin=WHEN
           BRANCH
             if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
               arg0: GET_VAR 'val tmp0_subject: kotlin.Int [val] declared in <root>.foo' type=kotlin.Int origin=null
diff --git a/compiler/testData/ir/irText/expressions/whileDoWhile.fir.txt b/compiler/testData/ir/irText/expressions/whileDoWhile.fir.txt
index 4cba37b1108..1940a72c661 100644
--- a/compiler/testData/ir/irText/expressions/whileDoWhile.fir.txt
+++ b/compiler/testData/ir/irText/expressions/whileDoWhile.fir.txt
@@ -61,7 +61,7 @@ FILE fqName:<root> fileName:/whileDoWhile.kt
     BLOCK_BODY
       VAR name:a type:kotlin.Any? [val]
         CONST Null type=kotlin.Nothing? value=null
-      WHEN type=kotlin.Any? origin=IF
+      WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=kotlin.Boolean
             GET_VAR 'val a: kotlin.Any? [val] declared in <root>.testSmartcastInCondition' type=kotlin.Any? origin=null
diff --git a/compiler/testData/ir/irText/lambdas/nonLocalReturn.fir.txt b/compiler/testData/ir/irText/lambdas/nonLocalReturn.fir.txt
index c63ffaa94e9..40cf61d9c90 100644
--- a/compiler/testData/ir/irText/lambdas/nonLocalReturn.fir.txt
+++ b/compiler/testData/ir/irText/lambdas/nonLocalReturn.fir.txt
@@ -44,7 +44,7 @@ FILE fqName:<root> fileName:/nonLocalReturn.kt
           FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> (it:kotlin.Int) returnType:kotlin.Unit
             VALUE_PARAMETER name:it index:0 type:kotlin.Int
             BLOCK_BODY
-              WHEN type=kotlin.Any? origin=IF
+              WHEN type=kotlin.Unit origin=IF
                 BRANCH
                   if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
                     arg0: GET_VAR 'it: kotlin.Int declared in <root>.testLrmFoo1.<anonymous>' type=kotlin.Int origin=null
@@ -62,7 +62,7 @@ FILE fqName:<root> fileName:/nonLocalReturn.kt
           FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> (it:kotlin.Int) returnType:kotlin.Unit
             VALUE_PARAMETER name:it index:0 type:kotlin.Int
             BLOCK_BODY
-              WHEN type=kotlin.Any? origin=IF
+              WHEN type=kotlin.Unit origin=IF
                 BRANCH
                   if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
                     arg0: GET_VAR 'it: kotlin.Int declared in <root>.testLrmFoo2.<anonymous>' type=kotlin.Int origin=null
diff --git a/compiler/testData/ir/irText/regressions/coercionInLoop.fir.txt b/compiler/testData/ir/irText/regressions/coercionInLoop.fir.txt
index 5d71d3b1943..f3d0683d9a6 100644
--- a/compiler/testData/ir/irText/regressions/coercionInLoop.fir.txt
+++ b/compiler/testData/ir/irText/regressions/coercionInLoop.fir.txt
@@ -13,7 +13,7 @@ FILE fqName:<root> fileName:/coercionInLoop.kt
         condition: CALL 'public abstract fun hasNext (): kotlin.Boolean declared in kotlin.collections.Iterator' type=kotlin.Boolean origin=null
           $this: GET_VAR 'val x: kotlin.collections.DoubleIterator [val] declared in <root>.box' type=kotlin.collections.DoubleIterator origin=null
         body: BLOCK type=kotlin.Int origin=null
-          WHEN type=kotlin.Any? origin=IF
+          WHEN type=kotlin.Unit origin=IF
             BRANCH
               if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
                 $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
diff --git a/compiler/testData/ir/irText/regressions/kt24114.fir.txt b/compiler/testData/ir/irText/regressions/kt24114.fir.txt
index 37f32d53337..dc4e9d4ef00 100644
--- a/compiler/testData/ir/irText/regressions/kt24114.fir.txt
+++ b/compiler/testData/ir/irText/regressions/kt24114.fir.txt
@@ -11,16 +11,16 @@ FILE fqName:<root> fileName:/kt24114.kt
     BLOCK_BODY
       WHILE label=null origin=WHILE_LOOP
         condition: CONST Boolean type=kotlin.Boolean value=true
-        body: BLOCK type=kotlin.Any? origin=WHEN
+        body: BLOCK type=kotlin.Unit origin=WHEN
           VAR IR_TEMPORARY_VARIABLE name:tmp0_subject type:kotlin.Int [val]
-          WHEN type=kotlin.Any? origin=WHEN
+          WHEN type=kotlin.Unit origin=WHEN
             BRANCH
               if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
                 arg0: GET_VAR 'val tmp0_subject: kotlin.Int [val] declared in <root>.test1' type=kotlin.Int origin=null
                 arg1: CONST Int type=kotlin.Int value=1
-              then: BLOCK type=kotlin.Any? origin=WHEN
+              then: BLOCK type=kotlin.Unit origin=WHEN
                 VAR IR_TEMPORARY_VARIABLE name:tmp1_subject type:kotlin.Int [val]
-                WHEN type=kotlin.Any? origin=WHEN
+                WHEN type=kotlin.Unit origin=WHEN
                   BRANCH
                     if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
                       arg0: GET_VAR 'val tmp1_subject: kotlin.Int [val] declared in <root>.test1' type=kotlin.Int origin=null
@@ -35,16 +35,16 @@ FILE fqName:<root> fileName:/kt24114.kt
     BLOCK_BODY
       WHILE label=null origin=WHILE_LOOP
         condition: CONST Boolean type=kotlin.Boolean value=true
-        body: BLOCK type=kotlin.Any? origin=WHEN
+        body: BLOCK type=kotlin.Unit origin=WHEN
           VAR IR_TEMPORARY_VARIABLE name:tmp2_subject type:kotlin.Int [val]
-          WHEN type=kotlin.Any? origin=WHEN
+          WHEN type=kotlin.Unit origin=WHEN
             BRANCH
               if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
                 arg0: GET_VAR 'val tmp2_subject: kotlin.Int [val] declared in <root>.test2' type=kotlin.Int origin=null
                 arg1: CONST Int type=kotlin.Int value=1
-              then: BLOCK type=kotlin.Any? origin=WHEN
+              then: BLOCK type=kotlin.Unit origin=WHEN
                 VAR IR_TEMPORARY_VARIABLE name:tmp3_subject type:kotlin.Int [val]
-                WHEN type=kotlin.Any? origin=WHEN
+                WHEN type=kotlin.Unit origin=WHEN
                   BRANCH
                     if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
                       arg0: GET_VAR 'val tmp3_subject: kotlin.Int [val] declared in <root>.test2' type=kotlin.Int origin=null